The present invention relates to a drive circuit connection structure suitable for use in a display apparatus, and particularly a connection structure including a drive semiconductor device connected to a periphery of a transparent substrate of a display panel constituting such a display apparatus and a circuit board connected to the semiconductor device for supplying input signals and a power to the semiconductor device.
Hitherto, there have been known display apparatus including flat display devices having display electrodes arranged in the form of, e.g., a matrix, such as EL display panels and liquid crystal display panels of the simple matrix-type and the active matrix-type. Such display apparatus have conventionally included a circuit connection structure including a transparent substrate, such as a glass substrate or a plastic substrate, provided with display electrodes arranged in the form of, e.g., a matrix; a flexible tape carrier package (TCP) loaded with a driver IC by the TAB (tape-automated bonding) method; and a print circuit board (PCB, hereinafter sometimes called xe2x80x9cPCB boardxe2x80x9d), connected in this order.
FIG. 12 and FIG. 13 (a view showing a 13-13 section in FIG. 12) illustrate an example of such a drive circuit connection structure for a flat display panel. Referring to these figures, the connection structure includes TCPs 4ap and 8p loaded with driver ICs (as drive semiconductor circuits) 5p and 9p and copper foil patterns 32 (as output electrodes), glass substrates 1ap and 1bp for a liquid crystal panel 1 having electrode terminals 12p extended to peripheries thereof, and ACFs (anisotropic conductive films or anisotropic conductive adhesive) 31 for heat-bonding the copper foil patterns 32 on the TCPs with the electrode terminals 12p on the glass substrates. Further, PCB boards 3p for supplying a power and control signals to the driver ICs 5p and 9p are connected with copper foil patterns 17 (as input electrodes) of the TCPs 4ap with solder 20p. 
The input electrodes and the output electrodes of each driver IC 5p are connected to the copper foil electrodes 17 and 32 on the input side and output side TCPs 4a, respective via gold bumps 15p. The connections of each driver IC 5p are sealed with a resinous sealing agent 16p. In such a display panel connection structure for a display apparatus as shown in FIGS. 12 and 13, as the display panel (particularly a liquid crystal panel) is provided with a larger number of display electrodes at a higher density, the connection pitch for connection between the output electrodes of the TCPs and the electrode terminals on the transparent substrates are decreased down to a required pitch of 50 xcexcm or smaller. However, according to a method for connecting TCP with a substrate as explained with reference to FIGS. 12 and 13, a very sophisticated and accurate bonding technique is required for ensuring such a minute connection pitch because of a limitation in size accuracy of TCPs and a deviation due to thermal expansion during connection by heat bonding of TCPS. Therefore, a connection structure as shown in FIG. 14 including bonding of driver ICs 5 to a substrate 1bp by a face-down mode has been proposed or ensuring such a minute connection pitch.
More specifically, referring to FIG. 14, the connection structure includes a connection by the face-down bonding mode of driver ICs 5 with electrode terminals extended to peripheries of a pair of glass substrates 1ap and 1bp of a display panel and with input electrodes (not shown) formed on the glass substrates 1ap and 1bp. The connection structure further includes flat cables 7a, 7b and 7c for supplying a drive power and control signals from an external control circuit.
However, in case where such a connection structure as shown in FIG. 14 is adopted in a display panel of a larger size, particularly a liquid crystal display panel of an enlarged size as desired, in recent years, the substrates 1ap and 1bp retain only narrow non-opposing peripheral areas while the input electrodes are increased in length, so that the input electrodes are caused to have a higher impedance, thus being liable to cause a delay in transmission of drive waveforms to the display or pixel electrodes leading to pixels.
In order to obviate the difficulty, it may be conceived of lowering the impedance of the input electrodes by forming the electrodes in a larger thickness, but the realization thereof is difficult in view of the limitations from the production process and size. Further, the increased impedance of the input electrodes is liable to cause a mal-function of data transfer during transmission of image data for a liquid crystal display panel of a higher definition to driver ICs.
A generic of the present invention is to solve the above-mentioned problems of the prior art.
A more specific object of the present invention is to provide a circuit connection structure capable of providing a lower input electrode impedance while ensuring a minute connection pitch.
Another object of the present invention is to provide a display apparatus including such a circuit connection structure.
According to the present invention, there is provided a circuit connection structure, comprising: a first substrate having electrode terminals formed thereon, a semiconductor device having first electrodes and second electrodes with the first electrodes connected to the electrode terminals of the first substrate, a flexible wiring member having thereon a pattern of conductors each extending from a first end to a second end on the flexible wiring member with the first ends of the conductors connected to the second electrodes of the semiconductor device, and a circuit board having thereon electrode terminals connected to the second ends of the conductors on the flexible wiring member.
It is preferred that the first and second electrodes of the semiconductor device are used as output electrodes and input electrodes, respectively, of the semiconductor device, so as to receive input data from the circuit board and supply output signals to the first substrate, thereby driving an electronic device including the first substrate.
The flexible wiring member may alternatively be constituted by a plurality of conductor wires each extending from a first end to a second end and not carried on a carrier film.
According to another aspect of the present invention, there is provided a display apparatus, comprising:
a display panel comprising at least one substrate having thereon pixel electrodes extending to form electrode terminals electrodes on a peripheral side of the substrate,
a semiconductor device having input electrodes, and output electrodes for supplying drive waveforms to the pixel electrodes of the display panel, and
a circuit board having electrode terminals for supplying an electric power and control signals to the semiconductor device; wherein
the electrode terminals on said at least one substrate of the display panel are connected to the output electrodes of the semiconductor device, and
the semiconductor device is connected to the circuit board via a flexible wiring member having thereon a pattern of conductors each extending from a first end to a second end so that the input electrodes of the semiconductor device are connected to the first ends of the conductors on the flexible wiring member, and the second ends of the conductors of the flexible wiring member are connected to the electrode terminals of the circuit board.
According to the circuit connection structure of the present invention, the first electrodes on one side of the semiconductor device may be connected to the electrode terminals on the first substrate which may carry pixel electrodes thereon via, e.g., an anisotropic conductive adhesive (ACF), etc., and without via a flexible wiring member according to the TAB method, thereby ensuring a minute connection pitch. On the other hand, the second electrodes on the other side of the semiconductor device are connected via conductors of the flexible wiring member to the electrode terminals of the circuit board. Particularly when the first and second electrodes of the semiconductor device are used as the output and input electrodes, respectively, the semiconductor device can be supplied with an electric power and control signals at a low impedance from the circuit board through the flexible wiring member and the second electrodes, and can supply output signals through the first electrodes at a minute arrangement pitch suitable for a high-definition output.
Particularly, if the circuit connection structure is included in a driver IC connection structure for a display apparatus including the first substrate as a substrate carrying pixel electrodes of a display panel and the circuit board for supplying an electric power and control signals to the driver IC, the semiconductor device can be supplied with input data at a low impedance and without mal-function and can supply drive signals to the display panel through the first electrodes arranged at a minute connection pitch suitable for a higher definition display.